Generally, multicasting refers to the delivery of data in a single transmission to multiple hosts. A switch, such as a distributed switch, forwards the multicast data (e.g., a multicast packet) sent to a multicast destination address to the correct hosts using multicast membership information. However, when the distributed switch does not have the multicast membership information for a multicast destination address, the distributed switch generally defaults to broadcasting or flooding the multicast packet to practically all hosts on a network (e.g., all hosts within a broadcast domain).
By flooding, the distributed switch ensures that the hosts of the group identified by the multicast destination address receive the multicast packet. However, flooding may also result in a waste of bandwidth and transmission of the multicast packet to unintended hosts, which may further pose a security risk. Flooding may also result in a waste of resources as each of the unintended hosts receiving the multicast packet may spend resources ultimately determining that it needs to discard the multicast packet, or the multicast packet is received by an unintended host and a security exposure may occur.